Using bond energy data, calculate the heat of formation of isoprene. Given that bond energy of C - H =98.8 kcal H - H =104 kcal , C - C =83 kcal , C = C =147 kcal and C (s) arrow C (g)=171 kcal

Question

Using bond energy data, calculate the heat of formation of isoprene. Given that bond energy of C - H =98.8 kcal H - H =104 kcal , C - C =83 kcal , C = C =147 kcal and C (s) arrow C (g)=171 kcal (A) 28.3 kcal (B) 20.6 kcal (C) 283 kcal (D) 220.6 kcal

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<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/23902c2a5119172d2918429f9a7f6e19-.png" /> Δ H = Sigma B ⋅ E . text (reactant)- Sigma B . E . text (product) Δ H =[5 B ⋅ E ⋅ C (s) arrow C (g)+4 B ⋅ E ⋅ H - H ] -[2 B . E ⋅ C - C +2 B ⋅ E C = C +8 B ⋅ E ⋅ C - H . Δ H =[5 × 171+4 × 104]-[2 × 83+2 × 147+8 × 98.8] =1271-1250.4=20.6 kcal

Q. Using bond energy data, calculate the heat of formation of isoprene. Given that bond energy of $C - H = 98.8 k c a l$ $H - H = 104 k c a l, C - C = 83 k c a l, C = C = 147 k c a l$ and $C_{(s)} \to C_{(g)} = 171 k c a l$

$28.3 k c a l$

$20.6 k c a l$

$283 k c a l$

$220.6 k c a l$

Q. Using bond energy data, calculate the heat of formation of isoprene. Given that bond energy of C−H=98.8kcal H−H=104kcal,C−C=83kcal,C=C=147kcal and C(s)​→C(g)​=171kcal

28.3kcal

20.6kcal

283kcal

220.6kcal

ΔH=ΣB⋅E.(reactant)​−ΣB.E.(product)​ ΔH=[5B⋅E⋅C(s)→C(g)​​+4B⋅E⋅H−H] −[2B.E⋅C−C+2B⋅EC=C​+8B⋅E⋅C−HΔH=[5×171+4×104]−[2×83+2×147+8×98.8] =1271−1250.4=20.6kcal

Q. Using bond energy data, calculate the heat of formation of isoprene. Given that bond energy of $C - H = 98.8 k c a l$ $H - H = 104 k c a l, C - C = 83 k c a l, C = C = 147 k c a l$ and $C_{(s)} \to C_{(g)} = 171 k c a l$

$28.3 k c a l$

$20.6 k c a l$

$283 k c a l$

$220.6 k c a l$